[英]Updating values in list of dictionaries
我有一個類似這樣的詞典列表:
users=[{"name": "David", "team": "reds", "score1": 100, "score2": 20,},
{"name": "David", "team": "reds", "score1": 20, "score2": 60,},
{"name": "David", "team": "blues", "score1": 10, "score2": 70,}]
並且真的想得到一個新的處理的字典列表
summary=[{"team": "reds", "total1": 120, "total2": 80,},
{"team": "blues", "total1": 120, "total2": 80,}]
最好只循環一次原始數據。 我可以創建一個字典,為每個用戶鍵保存一個總值
summary = dict()
for user in users:
if not user['team'] in summary:
summary[user['team']]=float(user['score1'])
else:
summary[user['team']]+=float(user['score1'])
給
summary = {'reds': 120,'blues': 10}
但我正在努力制作字典列表,我最接近的是在團隊的第一個實例創建一個字典,然后嘗試在后續事件中附加其值...
summary = []
for user in users:
if any(d['team'] == user['team'] for d in summary):
# append to values in the relevant dictionary
# ??
else:
# Add dictionary to list with some initial values
d ={'team':user['team'],'total1':user['score1'],'total2':user['score2']}
summary.append(dict(d))
......而且它變得凌亂......我是以完全錯誤的方式來做這件事的嗎? 你能改變列表中字典中的值嗎?
謝謝
我認為這是使用pandas
庫進行python的好例子:
>>> import pandas as pd
>>> dfUsers = pd.DataFrame(users)
>>> dfUsers
name score1 score2 team
0 David 100 20 reds
1 David 20 60 reds
2 David 10 70 blues
>>> dfUsers.groupby('team').sum()
score1 score2
team
blues 10 70
reds 120 80
如果你真的想把它寫成dict
:
>>> dfRes = dfUsers.groupby('team').sum()
>>> dfRes.columns = ['total1', 'total2'] # if you want to rename columns
>>> dfRes.reset_index().to_dict(orient='records')
[{'team': 'blues', 'total1': 10, 'total2': 70},
{'team': 'reds', 'total1': 120, 'total2': 80}]
另一種方法是使用itertools.groupby
:
>>> from itertools import groupby
>>> from operator import itemgetter
>>> users.sort(key=itemgetter('team'))
>>>
>>> res = [{'team': t[0], 'res': list(t[1])} for t in groupby(users, key=itemgetter('team'))]
>>> res = [{'team':t[0], 'total1': sum(x['score1'] for x in t[1]), 'total2': sum(x['score2'] for x in t[1])} for t in res]
>>> res
[{'team': 'blues', 'total1': 10, 'total2': 70},
{'team': 'reds', 'total1': 120, 'total2': 80}]
或者,如果你真的想要簡單的python:
>>> res = dict()
>>> for x in users:
if x['team'] not in res:
res[x['team']] = [x['score1'], x['score2']]
else:
res[x['team']][0] += x['score1']
res[x['team']][1] += x['score2']
>>> res = [{'team': k, 'total1': v[0], 'total2': v[1]} for k, v in res.iteritems()}]
>>> res
[{'team': 'reds', 'total1': 120, 'total2': 80},
{'team': 'blues', 'total1': 10, 'total2': 70}]
你真的很親密,你只需要一種方法來查找要更新的字典。 這是我能看到的最簡單的方法。
summary = dict()
for user in users:
team = user['team']
if team not in summary:
summary[team] = dict(team=team,
score1=float(user['score1']),
score2=float(user['score2']))
else:
summary[team]['score1'] += float(user['score1'])
summary[team]['score2'] += float(user['score2'])
然后
>>> print summary.values()
[{'score1': 120.0, 'score2': 80.0, 'team': 'reds'},
{'score1': 10.0, 'score2': 70.0, 'team': 'blues'}]
這里是我的解決方案,它會假設需要添加所有得分開始score
:
users=[{"name": "David", "team": "reds", "score1": 100, "score2": 20,},
{"name": "David", "team": "reds", "score1": 20, "score2": 60,},
{"name": "David", "team": "blues", "score1": 10, "score2": 70,}]
totals = {}
for item in users:
team = item['team']
if team not in totals:
totals[team] = {}
for k,v in item.items():
if k.startswith('score'):
if k in totals[team]:
totals[team][k] += v
else:
totals[team][k] = v
print totals
{'reds': {'score1': 120, 'score2': 80}, 'blues': {'score1': 10, 'score2': 70}}
請參閱內聯注釋以獲得解釋
import pprint
users=[{"name": "David", "team": "reds", "score1": 100, "score2": 20,},
{"name": "David", "team": "reds", "score1": 20, "score2": 60,},
{"name": "David", "team": "blues", "score1": 10, "score2": 70,}]
scores_by_team = dict()
for user in users:
if user['team'] not in scores_by_team:
# Make sure you're gonna have your scores zeroed so you can add the
# user's scores later
scores_by_team[user['team']] = {
'total1': 0,
'total2': 0
}
# Here the user's team exists for sure in scores_by_team
scores_by_team[user['team']]['total1'] += user['score1']
scores_by_team[user['team']]['total2'] += user['score2']
# So now, the scores you want have been calculated in a dictionary where the
# keys are the team names and the values are another dictionary with the scores
# that you actually wanted to calculate
print "Before making it a summary: %s" % pprint.pformat(scores_by_team)
summary = list()
for team_name, scores_by_team in scores_by_team.items():
summary.append(
{
'team': team_name,
'total1': scores_by_team['total1'],
'total2': scores_by_team['total2'],
}
)
print "Summary: %s" % summary
這輸出:
Before making it a summary: {'blues': {'total1': 10, 'total2': 70}, 'reds': {'total1': 120, 'total2': 80}}
Summary: [{'total1': 120, 'total2': 80, 'team': 'reds'}, {'total1': 10, 'total2': 70, 'team': 'blues'}]
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